| 1. |
- Evans, AO, et al.
(författare)
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High-spin structure beyond band termination in Er-157
- 2004
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Ingår i: Physical Review Letters. - 1079-7114. ; 92:25
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Tidskriftsartikel (refereegranskat)abstract
- The angular-momentum induced transition from a deformed state of collective rotation to a noncollective configuration has been studied. In Er-157 this transition manifests itself as favored band termination near I=45 (h) over bar. The feeding of these band terminating states has been investigated for the first time using the Gammasphere spectrometer. Many weakly populated states lying at high excitation energy that decay into these special states have been discovered. Cranked Nilsson-Strutinsky calculations suggest that these states arise from weakly collective "core-breaking" configurations.
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| 2. |
- Gorgen, A, et al.
(författare)
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Quadrupole moments of wobbling excitations in Lu-163
- 2004
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 69:3
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Tidskriftsartikel (refereegranskat)abstract
- Lifetimes of states in the triaxial strongly deformed bands of Lu-163 have been measured with the Gammasphere spectrometer using the Doppler-shift attenuation method. The bands have been interpreted as wobbling-phonon excitations from the characteristic electromagnetic properties of the transitions connecting the bands. Quadrupole moments are extracted for the zero-phonon yrast band and, for the first time, for the one-phonon wobbling band. The very similar results found for the two bands suggest a similar intrinsic structure and support the wobbling interpretation. While the in-band quadrupole moments for the bands show a decreasing trend towards higher spin, the ratio of the interband to the in-band transition strengths remains constant. Both features can be understood by a small increase in triaxiality towards higher spin. Such a change in triaxiality is also found in cranking calculations, to which the experimental results are compared.
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| 3. |
- Pavan, J, et al.
(författare)
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Lifetime measurements and terminating structures in Nb-87
- 2003
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 67:3: 034316
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Tidskriftsartikel (refereegranskat)abstract
- Two experiments have been performed using the Ni-58(S-32,3p) reaction at 135 MeV with Gammasphere and the Microball to study the high-spin structure of the transitional nucleus Nb-87. The first experiment using a thin target provided a considerable extension and refinement of the level scheme, as well as firm spin assignments from directional correlation of oriented nuclei. Sub-picosecond lifetimes were measured in the second backed-target experiment using the Doppler-shift attenuation method. The lifetimes imply a rather modest average deformation of beta(2)similar to0.1, but with considerable variation from state to state. Strong alternations were observed in the B(M1) strengths of transitions between some pairs of bands. The experimental results were compared with calculations performed within the cranked Nilsson-Strutinsky approach. The calculations generally reproduce the irregularities in the structure of the yrast lines and plunging transition quadrupole moments Q(t) within the bands explaining them as reflections of configuration changes and an approach of band termination, respectively.
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| 4. |
- Robinson, SD, et al.
(författare)
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High-spin structures and band termination effects in Cd-104
- 2002
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Ingår i: Journal of Physics G: Nuclear and Particle Physics. - : IOP Publishing. - 0954-3899. ; 28:6, s. 1415-1431
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in the neutron-deficient isotope Cd-104 were populated using the Cr-50(Ni-58,4p)Cd-104 reaction at a beam energy of 250 MeV The level scheme has been extended using triple gamma-ray coincidences to a spin of 29h and an excitation energy of 18.2 MeV. Several collective structures involving the excitation of h(11/2) neutrons have been observed to spins approaching 30h. The high-spin structure has been compared to the results of cranked Nilsson-Strutinsky calculations.
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| 5. |
- Singh, AK, et al.
(författare)
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Evidence for noncollective oblate structures at high spin in Cs-123
- 2004
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 70:3
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Cs-123 were populated in the Ni-64(Ni-64,p4n) reaction at a beam energy of 265 MeV. Gamma-ray coincidences were measured using the Gammasphere spectrometer. Two additional bands have been placed in the level scheme and the four previously known bands have been extended to higher spin. At the highest spins, two of the bands show irregular level sequences. These structures of noncollective excitations, which compete with collective rotation, are interpreted as band-terminating states. The results are compared to cranked Nilsson-Strutinsky calculations, and configuration assignments to the bands and to the terminating states are discussed.
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| 6. |
- Yu, CH, et al.
(författare)
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Rotational Bands with Terminating Properties in 59Ni
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 65:6
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Tidskriftsartikel (refereegranskat)abstract
- Highly-deformed rotational bands were established in Ni-59 using the Ca-40(Si-29,2p2alpha)Ni-59 reaction. Lifetime measurements indicate that transition quadrupole moments of two of these bands decrease as they smoothly approach their maximum-spin states. The configurations of these bands as well as their band-terminating features are discussed based on configuration-dependent cranked Nilsson-Strutinsky calculations. These calculations indicate that, unlike similar bands observed previously in the region, the two bands in Ni-59 maintain significant collectivity at their I=I-max states.
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